1 year m.pharm for 1 st semester accoring to syllabus.rate programmed DDS

1. Rate programmed drug delivery system
presented by:
Ajay kumar
submited to :
Dr. Shankaryya sir and prof. Venkatesh sir

2. Rate controlled drug delivery system
• Principles and fundamentals ; sustained release ,sustained action, controlled release
,extended action , time release dosage form are the terms used to identify drug delivery system
that are design to achieved a prolonged therapeutic effect by continuously releasing medication
over an extend period of time after the administer the single dose .
• the term controlled release has become associated with those system from which therapeutic
agent may be automatically delivered at predetermined rates over a long period of time.
• But, there are some confusion in terminology between “Controlled release” & “Sustained
release”
• Sustained Release :
• The term sustained release has been constantly used to describe a pharmaceutical dosage form
formulated to retard the release of a therapeutic agent such that its appearance in the systemic
circulation is delayed &/or prolonged & its plasma profile is sustained in duration.
• Controlled Release :
• Control release system is the one which delivers the drugs at a predetermined rate , locally or
systemically for a specific period of time.

3. An ideal controlled drug delivery system is the one which
delivers the drug at a predetermined rate, locally or
systematically for a specified period of time.

4. Advantages
• Less fluctuation in drug in blood levels.
• Reduction in dosing frequency
• Improved patient convenience and compliance.
• Avoidance of night time dosing .
• More uniform effect.
• Reduction in GI irritation and dose related side effect
Disadvantages:
 Decreased systemic availability in comparsion to immediate release
conventional dosage forms.
 Poor in vivo – in vitro correlation.
 Possibility of dose dumping .
 Higher cost of formulation.
 Retrieval of drug is difficult.

5. Type:
1. Rate preprogrammed drug delivery system
a. Polymer membrane permeation CDDS
b. polymer matrix diffusion CDDS
c. micro reservoir partition CDDS
2. Activation modulation drug delivery system
a. mechanically activated
b. pH activated
c. enzyme activated
d. osmotic activated
3. Feedback regulated drug delivery system
4. Site targeting drug delivery system

6. CONTENT
RATE CONTROLLED DRUG DELIVERY SYSTEM
 PRINCIPLE AND FUNDAMENTAL
 TYPES
1. RATE PRE PROGRAMMED DDS
a)polymer membrane permeation
b) polymer matrix diffusion
c) micro reservior cdds
2) ACTIVATION MODULATION DDS
a) mechanically activated dds
b)ph activated dds
c) enzyme activated dds
d) osmotic controlled activated dds
a) FEEDBACK REGULATED DDS
a) bioerosion regulated dds
b) bioresponsive dds
c) self regulated dds

7. Activation-Modulated drug delivery system
In this group of CRDDS , the release of drug molecules from the delivery system is
activated by some physical, chemical, biological process and facilitated by the
energy supplied externally.

8. CLASSIFICATION OF ACTIVATED DDS
A] physical means of activation
a. mechanically activated DDS
b. osmotic pressure activated DDS
d. vapour pressure activated DDS
e. magnetically activated DDS
f. sonophoresis activated DD
g. ionophoresis activated DDS
h. Hydration
B]chemical means of activation
a. PH activated drug delivery system
b. Ion activated DDS
c. Hydrolysis activated DDS
C]biochemical means of activation
a. enzyme activated DDS
b. biochemical activated DDS

9. mechanically activated CDDS
In this type ,drug reservoir is in solution form in a container
equipped with mechanically activated pumping system
Exg . METERED DOSE NEBULIZER.

10. PH activated DDS
• This type of activated CDDS permit targeting the delivery of a drug only in the
region with selected pH range.
Fig. a PH activated DDS and the PH dependent formation of microporous membrane
in the intestinal tract

11.  Enzyme activated CDDS
This type of system depend on the enzymatic process to activate the release of drugs.
In this system the drug reservoir is either physically entrapped in microspheres or chemically
bound to polymer chain from bio-polymers such as albumin or polypeptides .
The release of drug is activated by the enzymatic hydrolysis of the biopolymers by a specific
enzymes in the target tissue.
ex . developement of albumin microsphere that release 5-flurouracil in a
controlled manner by protease activated biodegradation.
fig . A typical example of enzyme activated CDDS which show the enzymatic process to
activate the release of drugs.

12. Osmotic controlled activated DDS
• This type of activation –controlled DDS depends on osmotic pressure
to activate the release of drug.
• In this type, drug reservoir can be either solution or solid formulation
contained within semipermeable housing with controlled water
permeability.
• The drug is activated to release in solution form at constant rate
through a special delivery orifice .
• The rate of drug release is modulated by controlling the gradient of
osmotic pressure.
• For the drug delivery system containing a solution formulation the
intrinsic rate of drug release is defined by

13. • For the drug delivery system containing a solid formulation, the intrinsic rate of
drug release is define by
Where,
Q/t =rate of drug release
Pw = water permeability of semipermeable housing
Am = effective S.A. of semipermeable housing
hm= thickness semipermeable housing
=differential osmotic pressure b/w the DDS with osmotic
pressure 𝜋𝑠and the environment with osmotic
pressure 𝜋𝑒
Sd = Aqueous solubility of the drug contained in the solid formulation
𝜋𝑠 − 𝜋𝑒

14. Rate controlling factor
• water permeability of the semi permeable membrane.
• Effective surface area of the semi permeable membrane.
• Osmotic pressure difference across the semi permeable membrane.
ex. Alzet osmotic pump

15. Feedback regulated drug delivery system
In this type rate of release of the drug has been activated by a
triggering agent , such as biochemical substance (in the body ) and
also regulated by its concentration via some feedback mechanism.

16. • They are further classified as;
a) Bioerosion – regulated DDS
b) Bioresponsive DDS
c) Self- regulated DDS
a) Bioerosion regulated DDS

17. b) Bioresponsive DDS
In this type , the drug reservoir is contained in a device enclosed by
bio – responsive membrane whose drug permeability is controlled by
concentration of biochemical agent.
Ex . Glucose-triggered insulin drug delivery system

18.  In this system ,the insulin reservoir is encapsulated within hydro gel
membrane having -NR2 group.
 in alkaline solution ,the –NR2 are neutral and the membrane is
unswollen and impermeable to insulin.
Glucose penetrate into the membrane , it oxidizes enzymatically by
the glucose oxidase entrapped in the membrane to form gluconic
acid.
The -NR2 group is protonated to form –NR2H and the hydro gel
membrane then becomes swollen and permeable to insulin
molecules.

19. C. Self – regulating DDS
This type of system depends on a reversible and competitive binding mechanism to
activate and to regulate the release of drug.
Drug reservoir is drug complex encapsulated within a semipermeable polymeric
membrane .
The release of drug from the delivery system is activated by the membrane
permeation of biochemical agent from the tissue in which the system is located .
ex. In the complex of glycosylated insulin concanavalin A, which is
encapsulated inside a polymer membrane . glucose penetrates into the system and it
activates the release of glycosylated insulin from the complex for controlled delivery
out of system.